阅读说明：本技术 提高变频器电路功率因数的有源前端整流变频器及方法 (Active front-end rectification frequency converter and method for improving power factor of frequency converter circuit ) 是由 佘利国 郑焕生 于 2021-07-15 设计创作，主要内容包括：本发明公开了一种提高变频器电路功率因数的有源前端整流变频器,包括预充电及主控制器、电网滤波单元、功能单元、控制单元以及检测单元,其特征在于：所述预充电及主控制器分别与检测单元和电网滤波单元连接,且检测单元与电网滤波单元同步连接,该装置设有自关断器件IGBT作为功率器件,并使用正弦脉宽调制技术,可以按需要在一定范围内设定,调节功率因数；整流后的直流母线电压可在一定范围内设定,当交流侧电网输入电压波动时,直流母线电压稳定,以保证当输入电压偏低时,变频器仍能正常工作；电机侧制动后的能量通过逆变器返回,而使直流母线电压升高时,则调节交流输入电流的相位,从而提高电路功率。(The invention discloses an active front-end rectification frequency converter for improving the power factor of a frequency converter circuit, which comprises a pre-charging and main controller, a power grid filtering unit, a functional unit, a control unit and a detection unit, and is characterized in that: the device is provided with a self-turn-off device IGBT serving as a power device, and a sinusoidal pulse width modulation technology is used, so that the power device can be set within a certain range as required to adjust a power factor; the rectified direct-current bus voltage can be set within a certain range, and when the input voltage of the alternating-current side power grid fluctuates, the direct-current bus voltage is stable, so that the frequency converter can still work normally when the input voltage is low; the energy after the motor side braking is returned through the inverter, and when the voltage of the direct current bus is increased, the phase of the alternating current input current is adjusted, so that the circuit power is improved.)

1. The utility model provides an improve active front end rectification converter of converter circuit power factor, includes precharge and main control unit, electric wire netting filter unit, functional unit, the control unit and detecting element, its characterized in that: the pre-charging and main controller is respectively connected with the detection unit and the power grid filtering unit, the detection unit is synchronously connected with the power grid filtering unit, the detection unit is connected with the control unit, the control unit comprises an A/D chip, a converter and a microprocessor, the A/D chip and the microprocessor are respectively connected with the rectifying unit and the inverting unit correspondingly, the rectifying unit and the inverting unit are mutually connected and form a functional unit, one end of the functional unit is connected with the power grid filtering unit, and the other end of the functional unit is connected with a motor of the frequency converter.

2. The specific operating method of an active front-end rectifying frequency converter for improving the power factor of the frequency converter circuit according to claim 1, wherein: firstly, after a starting signal of a frequency converter is sent to an inversion unit main control board, the starting signal is sent to a rectification unit main control board through a control circuit board; after the main control board of the rectifying unit is started, triggering a voltage detection board, detecting the voltage value and the phase of three-phase voltage at the power grid side, and completing power grid synchronization; after the synchronization of the power grid is finished, the voltage detection board gives a pre-charging signal to control the incoming line main relay to be attracted, the middle loop starts pre-charging, and the voltage of the direct current bus is adjusted to a set value; after the process is finished, the inverter unit driving circuit is allowed to work, and the frequency converter system starts to normally operate.

3. The active front-end rectifier converter and method for improving power factor of a converter circuit as claimed in claim 2, wherein: the voltage detection board performs pulse sampling on input voltage of the power grid side, the obtained analog voltage is sent to the A/D chip, digital quantity is sent to the microprocessor for operation after analog-digital conversion, and the phase position of the power grid voltage is obtained.

4. The active front-end rectifier converter and method for improving power factor of a converter circuit as claimed in claim 2, wherein: after the power grid voltage is synchronized, the main control board of the rectification unit gives out sine wave pulse width modulation signals, so that the upper bridge arm and the lower bridge arm of the IGBT module are alternately conducted according to a program set time sequence.

5. The active front-end rectifier converter and method for improving power factor of a converter circuit as claimed in claim 2, wherein: when the voltage on the power grid side fluctuates, the duty ratio of the IGBT driving signal is adjusted, so that the voltage of the direct-current bus can be kept stable.

6. The active front-end rectifier converter and method for improving power factor of a converter circuit as claimed in claim 2, wherein: the structure of the inversion unit is opposite to that of the rectification unit, and the main control board of the inversion unit gives sine wave pulse width modulation signals to enable upper and lower bridge arms of the IGBT module to be alternately conducted according to a program set time sequence. And inverting the direct current output by the rectifying unit to be converted into three-phase alternating current output to control the motor to operate.

Technical Field

The invention relates to the technical field of motor control, in particular to an active front-end rectification frequency converter and a method for improving the power factor of a frequency converter circuit.

Background

The rectifying unit of the traditional frequency converter control system mostly adopts diode rectification or silicon controlled rectifier rectification. Although the circuit is low in cost and simple in maintenance, the rectified direct current bus has many higher harmonics, and the elements of the rear-end inverter part are easily damaged. The direct current bus current is conducted in a single direction, energy feedback is avoided, and a brake resistor needs to be configured. And the voltage of the direct current side is uncontrollable, so that the power factor is low and the energy loss is large. When the power grid fluctuates, the rectified direct current voltage may be lower than the rated voltage of the motor, so that the motor cannot work normally.

The active front-end rectifier uses a self-turn-off device IGBT as a power device and uses a sine pulse width modulation technology. Because the voltage and current waveforms at the front end of the rectifier are filtered into sine waveforms, the phase difference angle between the voltage and current waveforms can be set within a certain range as required to adjust the power factor. The rectified DC bus voltage can be set within a certain range, and when the input voltage of the AC side power grid fluctuates, the DC bus voltage is stable, so that the frequency converter can still work normally when the input voltage is low. When the energy after the motor side braking is returned through the inverter and the voltage of the direct current bus is increased, the phase of the alternating current input current is adjusted. The phase of the current is opposite to the phase of the power supply voltage, so that the regenerative power generation operation is realized, and the regenerative power is fed back to the alternating current power grid.

Disclosure of Invention

The present invention is directed to an active front-end rectification converter and a method for improving the power factor of the converter circuit, so as to solve the problems mentioned in the background art.

The purpose of the invention is realized by the following technical scheme:

the utility model provides an improve active front end rectification converter of converter circuit power factor, is including precharging and main control unit, electric wire netting filtering unit, functional unit, the control unit and detecting element, precharging and main control unit are connected with detecting element and electric wire netting filtering unit respectively, and detecting element and electric wire netting filtering unit synchronous connection, the detecting element is connected with the control unit, the control unit includes AD chip, converter and microprocessor, AD chip and microprocessor correspond respectively and are connected with rectifying unit and contravariant unit, rectifying unit and contravariant unit interconnect constitute functional unit, functional unit one end is connected in electric wire netting filtering unit, and the other end is connected with the motor of converter.

Furthermore, the specific working method of the active front-end rectification frequency converter for improving the power factor of the frequency converter circuit comprises the steps of firstly sending a starting signal of the frequency converter to the main control board of the inversion unit, and then sending the starting signal to the main control board of the rectification unit through the control circuit board; after the main control board of the rectifying unit is started, triggering a voltage detection board, detecting the voltage value and the phase of three-phase voltage at the power grid side, and completing power grid synchronization; after the synchronization of the power grid is finished, the voltage detection board gives a pre-charging signal to control the incoming line main relay to be attracted, the middle loop starts pre-charging, and the voltage of the direct current bus is adjusted to a set value; after the process is finished, the inverter unit driving circuit is allowed to work, and the frequency converter system starts to normally operate.

Further, the voltage detection board performs pulse sampling on input voltage of the power grid side, the obtained analog voltage is sent to the A/D chip, and digital quantity is sent to the microprocessor for operation after analog-to-digital conversion, so that the phase of the power grid voltage is obtained.

Further, after the power grid voltage is synchronized, the main control board of the rectification unit gives out sine wave pulse width modulation signals, so that the upper bridge arm and the lower bridge arm of the IGBT module are alternately conducted according to a program set time sequence.

Furthermore, when the voltage on the power grid side fluctuates, the duty ratio of the IGBT driving signal is adjusted, so that the voltage of the direct-current bus can be kept stable.

Furthermore, the structure of the inverter unit is opposite to that of the rectifier unit, and the main control board of the inverter unit gives out sine wave pulse width modulation signals to enable the upper bridge arm and the lower bridge arm of the IGBT module to be alternately conducted according to a program set time sequence. And inverting the direct current output by the rectifying unit to be converted into three-phase alternating current output to control the motor to operate.

Compared with the prior art, the active front-end rectification frequency converter and the method for improving the power factor of the frequency converter circuit have the advantages that the IGBT serving as the self-turn-off device is arranged as the power device, the sine pulse width modulation technology is used, and the power factor can be set within a certain range as required to be adjusted; the rectified direct-current bus voltage can be set within a certain range, and when the input voltage of the alternating-current side power grid fluctuates, the direct-current bus voltage is stable, so that the frequency converter can still work normally when the input voltage is low; when the energy after the motor side braking is returned through the inverter and the voltage of the direct current bus is increased, the phase of the alternating current input current is adjusted. The phase of the current is opposite to the phase of the power supply voltage, so that the regenerative power generation operation is realized, and the regenerative power is fed back to the alternating current power grid.

Drawings

FIG. 1 is an overall schematic diagram of an active front-end rectifier converter and method of the present invention for improving the power factor of the converter circuit;

FIG. 2 is a schematic diagram of a voltage sense board of the active front-end rectifier converter and method of the present invention for improving the power factor of the converter circuit;

FIG. 3 is a schematic diagram of a rectifying unit of the active front-end rectifying converter and method of the present invention for improving the power factor of the converter circuit;

FIG. 4 is a waveform diagram of a rectifying unit of the active front-end rectifying converter and method of the present invention for improving the power factor of the converter circuit;

FIG. 5 is a functional block diagram of a main control board of the active front-end rectifier converter and method of the present invention for improving the power factor of the converter circuit;

FIG. 6 is a schematic diagram of an inverter unit of the active front-end rectifier converter and method of the present invention for increasing the power factor of the converter circuit;

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and all other embodiments obtained by a person of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the protection scope of the present invention.

As shown in fig. 1-6, the present invention discloses an active front-end rectification frequency converter for improving the power factor of a frequency converter circuit, which comprises a pre-charging and main controller, a power grid filtering unit, a functional unit, a control unit and a detection unit, wherein the pre-charging and main controller is respectively connected with the detection unit and the power grid filtering unit, the detection unit is synchronously connected with the power grid filtering unit, the detection unit is connected with the control unit, the control unit comprises an a/D chip, a converter and a microprocessor, the a/D chip and the microprocessor are respectively and correspondingly connected with the rectification unit and the inversion unit, the rectification unit and the inversion unit are mutually connected to form the functional unit, one end of the functional unit is connected with the power grid filtering unit, and the other end of the functional unit is connected with a motor of the frequency converter.

According to the specific working method of the active front-end rectification frequency converter for improving the power factor of the frequency converter circuit, firstly, a starting signal of the frequency converter is sent to an inversion unit main control board, and then the starting signal is sent to the rectification unit main control board through a control circuit board; after the main control board of the rectifying unit is started, triggering a voltage detection board, detecting the voltage value and the phase of three-phase voltage at the power grid side, and completing power grid synchronization; after the synchronization of the power grid is finished, the voltage detection board gives a pre-charging signal to control the incoming line main relay to be attracted, the middle loop starts pre-charging, and the voltage of the direct current bus is adjusted to a set value; after the process is finished, the inverter unit driving circuit is allowed to work, and the frequency converter system starts to normally operate.

Further, the voltage detection board performs pulse sampling on input voltage of the power grid side, the obtained analog voltage is sent to the A/D chip, and digital quantity is sent to the microprocessor for operation after analog-to-digital conversion, so that the phase of the power grid voltage is obtained.

In the invention, after the power grid voltage is synchronized, the main control board of the rectification unit gives out sine wave pulse width modulation signals, so that the upper bridge arm and the lower bridge arm of the IGBT module are alternately conducted according to a program set time sequence.

According to the invention, when the voltage on the power grid side fluctuates, the duty ratio of the IGBT driving signal is adjusted, so that the voltage of the direct current bus can be kept stable.

In the invention, the structure of the inversion unit is opposite to that of the rectification unit, and the main control board of the inversion unit gives out sine wave pulse width modulation signals to ensure that the upper bridge arm and the lower bridge arm of the IGBT module are alternately conducted according to a program set time sequence. And inverting the direct current output by the rectifying unit to be converted into three-phase alternating current output to control the motor to operate.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.